trouble with colours

Questions and answers about processing in StarTools and how to accomplish certain tasks.

trouble with colours

Postby Rkonrad » Fri Sep 30, 2016 3:35 am

I recently had the fortune of visiting a dark site (imaging for the first time not off my driveway!) and acquired data on m31. Dew was collecting and unfortunately I only got 45 min of data from my zoom dslr lens: f/8, iso 400. The image is certainly not great but considering how little light I actually collected I'm mildly impressed with the detail. I'm really finding it impossible to get the colours any where close to what they should be. There's an abundance of green despite using "cap-green" Is this because there was only 45 min of exposure? I thought I would attach a link to an edited image as well as the unprocessed file. I stacked darks, flats and lights under Regim. Thanks!!

https://www.dropbox.com/sh/cj13iturbxzy ... ioGwa?dl=0

Richard
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Re: trouble with colours

Postby admin » Fri Oct 07, 2016 3:36 am

Hi Richard,

I had a look at the data and something rather strange is going on with your data!
I'm thinking there might be something wrong with your settings in Regim with regards to the debayering matrix you're using. Some channels may be swapped.

I would also strongly suggest you apply dithering (if possible) next time - there is a lot of pattern ("walking"/"streaking") noise visible.

Do let me know how you get on!
Ivo Jager
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Re: trouble with colours

Postby Rkonrad » Fri Oct 07, 2016 6:43 pm

Thanks Ivo,

I just noticed that I hadn't selected dcraw in preferences - that's probably why. I'm re-stacking as I type. I don't auto guide (yet) so dithering is probably not possible. If I set the slew for a very slow speed and nudge it between shots - could that work? Thanks!
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Re: trouble with colours

Postby Rkonrad » Fri Oct 07, 2016 7:03 pm

The result is equally bizarre after processing the newly stacked image.. I guess I should contact the developer of Regim. .
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Re: trouble with colours

Postby admin » Sun Oct 09, 2016 12:06 am

Hmmm... If you use dcraw (if you're comfortable with the command line) to debayer one of the light frame RAWs yourself, do you get the same sort of output?
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Re: trouble with colours

Postby admin » Sun Oct 09, 2016 12:12 am

Oh, that's nice!
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Re: trouble with colours

Postby Rkonrad » Mon Oct 10, 2016 4:50 pm

I think I missed something. ...What's nice?
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Re: trouble with colours

Postby admin » Wed Oct 12, 2016 12:48 am

Apologies - I responded to the wrong message :oops:

How did you get on with Regim?
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Re: trouble with colours

Postby Rkonrad » Fri Oct 14, 2016 8:41 pm

To be honest, I'm having success with DSS plus I've discovered DarkMaster which matches the darks and lights of the same or similar temperature. It produces a file which tells DSS what to do - amazing. Unfortunately it doesn't work well under Linux. Maybe I'll work on the Regim problem some other time.

Cheers

Richard
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Re: trouble with colours

Postby smokey688i » Fri Dec 16, 2016 3:40 pm

Richard,

Try turning bicubic interpolation on in Regim in the register tab. I had very similar issues with Regim at first, but running a stack with bicubic interpolation on fixed it. This fix also worked for a friend of mine who had the same issue. I'm curious if it works for you. I think you'll find the Regim output is easier to process in Startools, probably attributable to DSS always white balancing the data, regardless of the settings.

Chris
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